The present invention relates to an apparatus for measuring the concentration of various substances, for example, hemoglobin, bilirubin and the like, in the blood in a living tissue.
Conventionally, the measurement of the concentration of a substance in the blood has been effected invasively. More specifically, a blood sample is collected from the patient, and the thus-collected blood analyzed to measure the concentration of the predetermined substance in question.
With this method, however, it is difficult to frequently conduct the measurement, and each time the measurement is effected, the subject suffers pain.